Researchers develop non-flammable lithium-ion battery

Researchers have now developed a type of lithium-ion battery that, unlike conventional ones, consists entirely of solid chemical compounds and is non-flammable.

Lithium-ion batteries store a lot of energy in a small space, making them the energy source of choice for mobile electronic devices. Today, mobile phones, laptops, e-bikes and electric cars are all powered by such batteries.

But conventional lithium-ion batteries are not without their dangers: mobile phone batteries have exploded several times in the past, resulting in injuries.

Thanks to the solid electrolyte used in the new battery, one can not only operate batteries at higher temperatures, but also build thin-film batteries, that can even be directly placed on silicon chips.

"These thin-film batteries could revolutionise the energy supply of portable electronic devices," said lead researcher Jennifer Rupp, Professor of Electrochemical Materials at ETH Zurich in Switzerland.

In conventional lithium-ion batteries as well as in most other batteries, the positive and negative poles - the two electrodes - are made of solid conductive compounds; charges move between these electrodes in a liquid or gel electrolyte.

If you charge such a battery improperly (overcharging) or leave it sitting out in the sun, the liquid can ignite or the gel can swell up.

This is not the case with solid-state batteries. In these types of batteries, both the electrodes and the intermediary electrolyte are made of solid material.

"Solid electrolytes do not catch fire even when heated to high temperatures or exposed to the air," Rupp explained.

"In this work we have for the first time built a whole lithium-ion battery with a solid lithium garnet electrolyte and a solid minus pole made of an oxide-based material. Thus, we have shown that it is possible to build whole batteries based on lithium garnet," she said.